In conventional techniques for molding polymeric articles, granular or powder particles of a polymeric material are melted and injected into a mold at high temperatures under suitable pressures. The polymer melt is then cooled until the article reaches a point where it is sufficiently rigid to allow its removal from the mold. While the cooling time for relatively small articles is satisfactory in many applications, when the article which is being fabricated is relatively large the cooling time can be significantly long thereby making a conventional molding operation slow and expensive when forming large plastic articles. It is estimated that the cooling time tends to increase as the square of a typical dimension of the piece which is being formed so that conventional techniques for molding articles from polymer thermoplastic become substantially non-competitive unless the article is either limited in its overall size or limited in the thickness thereof.